Today, several news outlets reported on a letter written by former President Jimmy Carter along with other Nobel laureates against Keystone XL. Considering that the usual suspects – NRDC and the Sierra Club – were behind the effort, it’s no surprise that the letter rehashes opponents’ climate claims, which have been debunked time and time again.

In response to the Carter letter, Bloomberg asked an interesting question: how many big name or “celebrity” supporters can either side claim in the Keystone XL debate? As Bloomberg states, Keystone XL opponents “can point to actors Robert Redford, Daryl Hannah, and Jared Leto as allies.”

While opponents tout Hollywood actors, an overwhelming number of climate, energy, and national security experts have come out in support of Keystone XL.

National security experts such as General Jim Jones, former State Department special envoy and coordinator for international energy affairs David Goldwyn, and former Secretary of State George P. Shultz have been calling on President Obama to approve Keystone XL to increase our energy security and national security. Former Obama national security advisor Thomas E. Donilon said that he “probably would” advise approval of Keystone XL.

Other former Obama administration officials have also weighed in: former Secretary of the Interior Ken Salazar and former Obama U.S. Geological Survey chief Marcia McNutt have endorsed Keystone XL. Let’s not forget that EPA Administrator Gina McCarthy exposed Keystone XL opponents’ claims as false when she said that Keystone XL won’t affect EPA’s work on climate and “If there’s oil there, someone will find it and use it.” And, as the Washington Post recently reported “many government officials privately back the project on the grounds that it would expand the oil supply the U.S. would receive from a trusted ally, as well as bolster our relationship with Canada more broadly.”

The support for Keystone XL also clearly transcends political parties. Long-time Obama supporter Warren Buffet said Keystone XL is a “good idea for the country.” Former Presidents George Bush and Bill Clinton both support Keystone XL. Just last week, eleven Senate Democrats wrote a letter to President Obama urging him to let his “final decision be the right one, finding that the Keystone XL pipeline is in the national interest.”

Union and labor groups have rallied at the White House and across the country for Keystone XL jobs. As the Laborers’ International Union of North America (LIUNA) explained in a recent letter, “unemployed construction workers desperately need the work” and Keystone XL is a “lifeline” for thousands of members.

Of course, the State Department found, for the fifth time in over five years of research, that Keystone XL would have a negligible impact on the environment. IHS CERA also found that Keystone XL will have “no material impact” on greenhouse gas emissions. In fact, as Dan Yergin, IHS CERA founder and one of foremost energy experts put it, “The big winner from not building Keystone is Venezuela, because their heavy oil has the same carbon footprint as the oil sands. [So] Venezuela or Canada, take your pick. Who is your favorite country and who is your neighbor?”

As for opponents’ argument on climate – what have the experts had to say?

David Victor, a climate-policy expert at the University of California: “As a serious strategy for dealing with climate, blocking Keystone is a waste of time. But as a strategy for arousing passion, it is dynamite.”

David Keith, climate scientist at Harvard: “The extreme statements – that this is ‘game over’ for the planet – are clearly not intellectually true…”

Michael Levi, senior fellow for energy and environment at Council on Foreign Relations: “And despite fears by climate change activists that increased oil sand production has profoundly negative consequences to global warming, Alberta’s massive reserve base contributes relatively little to the problem at a global scale.”

EPA Administrator Gina McCarthy on Keystone XL: “We have been making great strides forward. No one project is going to take that away from us, but we are going to keep building on that success moving forward.”

Fatih Birol chief economist of the International Energy Agency (IEA): “…but the difference in getting oil from oil sands when compared to conventional oil, it is such a small contribution that it will be definitely wrong to highlight this as a major source of carbon dioxide emissions worldwide.”

Hundreds of editorials across the country have called for the construction of Keystone XL, and poll after poll has shown overwhelming support for the jobs and energy security that the pipeline brings.

If it comes down to the question: whom do the American people trust on Keystone XL: activists and Hollywood celebrities or climate, energy and national security experts? The decision is pretty clear.